In order to place the invention in the context of prior art, we first refer to FIG. 1. FIG. 1 shows a dialysis machine 300 for performing the hemodialysis treatment of a patient 10 in a dialysis operation. Alternatively or additionally, the dialysis machine 300 may also be designed to perform hemofiltration or hemodiafiltration and may also comprise a dialysate flow path or a dialysate fluid circuit 40, hereinafter also referred to as the dialysate circuit 40, a blood flow path or blood circuit 20 located extracorporeally of the patient 10, and a dialyzer apparatus 100 having an internal volume portion 120 and a membrane filter device 190 located therein having a membrane. The dialyzer apparatus 100 treats the blood of the patient 10, for example, via a hemodialysis treatment because the exchange of materials between the blood of the patient 10 flowing through the blood circuit 20 and the dialysate flowing through the dialysate circuit 40 occurs therein or in the membrane disposed therein. Here and in the text below, the term “dialysate” is intended to refer to the dialysate liquid and/or to the dialysate liquid used.
The membrane of the membrane filter device 190 spatially separates the internal volume portion 120 to form the blood region 130 through which the blood of the patient 10 flows and the dialysate region 170 through which the dialysate flows. The exchange of materials through the membrane includes the passage of substances normally excreted with urine, some of them toxic, through the membrane into the dialysate caused by a concentration gradient in the blood of said substances and, vice versa, the passage of substances dissolved in the prepared dialysate through the membrane and into the blood of the patient caused by a concentration gradient of said substances in the dialysate. The substances contained in the prepared dialysate are added to and dissolved in the dialysate via components 42, 44, 54 of the dialysate preparation in a distribution of concentrations specifically prepared for the patient 10.
Devices are known with which measurements of parameters may be made outside of the dialyzer apparatus 100, from which conclusions may be drawn regarding the performance, for example, the dialysance, of the dialyzer apparatus or the clearance of the extracorporeal blood circuit. Corresponding methods for analyzing the parameters measured by said devices and for providing information regarding the performance of a dialyzer apparatus are also known.